GPIO0 = Normally floating but this needs to be grounded when you start the update.

GPIO2 = high level

UTXD = Tx data connect to RX on FTDI/Serial interface

URXD = Rx data connect to TX of FTDI/Serial interface

English Version: Please refer to the NodeMCU flasher user guide.

Chinese Version: Please see the next step below

2. Open the software, choose the right COM and click the button that is circled in the following picture. When a tick appears in the bottom-left corner, it suggests that the firmware upgrade successfully.

3. This software contains an existing firmware, but if you want to upgrade other ESP8266 firmware, please click the button that is circled in the following picture, and only two file paths are available to choose.